Biologically-inspired visual scanning sensor for stabilization and tracking

Describes a sensor designed to ensure the non-contact stabilization of a craft and especially to deal with disturbance problems such as those resulting from slow speed angular drift. A low-cost, low-complexity active vision system is described, which is based on the specific eye movements occurring in the compound eye of the fly. In our system, motion is detected and processed by a local motion detector circuit (LMD). First, the rotation of two photosensors at a constant angular speed was simulated, which emphasized motion processing as a useful means of detecting variably contrasted objects, however far ahead they are located. Secondly, we reasoned that if the pair of photosensors turns at a varying angular speed the signal delivered by the LMD will vary depending on the position of the contrast feature located in the sensor´s visual field. The validity of this reasoning was then tested by constructing a miniature scanning sensor, the output voltage of which turned out to be a quasi-linear function of the position of the contrast feature present in the visual field and to be largely independent of the distance and the level of contrast. This output can therefore be used to generate the appropriate motor commands for stabilizing a sensory platform subject to yaw, pitch, or roll in relation to environmental features and/or for tracking contrasting objects